title: Chinese hamster ovary cells deficient in peroxisomes lack the nonspecific lipid transfer protein (sterol carrier protein 2).
abstract: Chinese hamster ovary cells deficient in intact peroxisomes were compared with wild type cells for the presence of the nonspecific lipid transfer protein (nsL-TP; sterol carrier protein 2). With the immunoblotting technique using the affinity purified antibody against rat liver nsL-TP, this protein was shown to be present in the homogenates from wild type cells, but could not be detected in mutant cells. In agreement with a previous study using livers from Zellweger patients it appears that there is a positive, as yet unknown, correlation between peroxisomes and the occurrence of nsL-TP in the cell. As a control using the affinity-purified antibody against the phosphatidylinositol transfer protein from bovine brain, levels of this protein were found to be normal in mutant cells. By use of metrizamide density gradients, nsL-TP was shown to cosediment with a membrane fraction different from peroxisomes. A protein of 58,000 daltons cross-reactive with the antibody against nsL-TP did cosediment with the peroxisomes in wild type cells and possibly with a "peroxisomal remnant" in the mutant cells. Incubation of wild type and mutant cells with L-[3-14C]serine showed that the biosynthesis of phosphatidylserine and the subsequent conversion into phosphatidylethanolamine was comparable in both cell types. This indicates that nsL-TP is not involved in the translocation of phosphatidylserine from the endoplasmic reticulum to the mitochondria as the site of decarboxylation.
authors.affiliation: Centre for Biomembranes and Lipid Enzymology, State University of Utrecht, The Netherlands.
authors.forename: G P
authors.initials: GP
authors.lastname: van Heusden
authors.forename: K
authors.initials: K
authors.lastname: Bos
authors.forename: C R
authors.initials: CR
authors.lastname: Raetz
authors.forename: K W
authors.initials: KW
authors.lastname: Wirtz
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics*; D002458:Cell Fractionation; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D015151:Immunoblotting; D008830:Microbodies / Q000648:ultrastructure*; D008970:Molecular Weight; D009154:Mutation; D010053:Ovary; D010716:Phosphatidylinositols / Q000378:metabolism; D010940:Plant Proteins; D013261:Sterols / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D010716:Phosphatidylinositols; D010940:Plant Proteins; D013261:Sterols; C072087:sterol carrier proteins